


Instinct

by Angelicesque (Hellionesque)



Category: Neon Genesis Evangelion
Genre: Alien Biology, Anal Sex, Blow Jobs, Body Horror, Eggs, Insectoid Alien, Large Insertion, M/M, Monsters, Oops! Bug Sexy, Oviposition, Shinji is Really Into It, Size Difference, Technically Bottom Kaworu, Technically Top Shinji, Telepathy, Weird Fluff
Language: English
Status: Completed
Published: 2019-03-06
Updated: 2019-03-06
Packaged: 2019-11-12 18:24:36
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,098
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18016034
Author URL: https://archiveofourown.org/users/Hellionesque/pseuds/Angelicesque
Summary: Shinji loves Kaworu. Even if love entails spending a week inside a room with a large insect that really likes how he tastes.Actually, especially if love entails that.





	Instinct

**Author's Note:**

> It’s time to get WEIRD

It was nearly time.

Shinji had been preparing for Kaworu’s yearly mutation for about half a month now, and the signs were starting to show. Increased hunger, not wanting to go outside, lethargy, aggressive and destructive behaviors, and a voracious sexual appetite were basically the works at this point, and were nothing new to him.

What was new, however, was the environment. They had just moved out to the edge of town, into a quiet and sparsely populated neighborhood. It was such a change from the constant noise of the city, and Shinji honestly didn’t know what to think. While it was quieter, something about being so far from any large city center was nerve racking. If anything, he should be happy.

Shinji wakes up to a sinking feeling in his stomach. It was so… quiet. Rubbing his eyes, he sits up and looks out the window, the soft grey sky making the world seem so small and dark. The coolness of the day seeps in through the cracks around it, and he shivers in the cold, empty bed. 

Rubbing his eyes, he tosses his legs over the side of the bed and stands up, stretching as he picks up his discarded shirt from the night prior to pull over his scratched shoulders. The fabric brushing over the light wounds makes him wince, but he brushes it off as he makes his way out of the room and down the hallway, stopping in front of the closed guest room door to press his ear against it.

There weren’t any discernible noises coming from the other side, but the shuffling of fabric and low sighs are all he needs to hear to move open the door.

“Kaworu…” Shinji calls in as soft of a voice as he could manage, the noises instantly stopping to instead be replaced by a rumbling growl. Turning the handle of the door, he slowly opens it and peers inside, his eyes meeting pair after pair of glowing red that stare back at him from the darkness of the room. “Oh…”

It seemed that the mutation had come early that year… which meant, to his dismay, that on the other side of the door was a creature of unknowable thoughts and immense power. Shinji had faced the beast once before, prior to satiating it’s desires, and he still had the scars to prove it.

Before he can even begin to close the door, it was already upon him. Despite their history together, Shinji knew that the beast that now had a massive, clawed hand wrapped around his face barely knew who he was, following baseline desires like _hungry_ or _angry_ or, hopefully, _horny_ , with little regard for input from the human now held in all six of its arms. Shinji grips desperately at one of its chest chitons as he wriggles uselessly in its grip, his back slammed firmly against the wall behind him as numerous sensory receptors brush over his skin, tasting and smelling every inch of him until it tenses, detecting its own scent on the surface of his skin as well as inside of him where it had been previously.

Shinji was more than thankful of the night prior, shifting his thighs uncomfortably together as he feels the thin gossamer stretching from the crevasses in its shell to touch and taste the area between his legs, moaning involuntary into the hot, leathery palm pressed against his mouth. 

Shinji gasps out loud as it lifts its scaly hand from his face, allowing him to breathe and finally look at the creature before him. It was, obviously, Kaworu; the semi-translucent and iridescent exoskeleton as well as its blood red ocular slits saying as much, though he does an extra sweep to check for any external discrepancies just to make sure nothing was wrong. All of its triple jointed arms and digitigrade legs were holding him much more carefully now, pupils fluctuating wildly as the hairline seams of its face split to reveal a segmented maw of dangerously sharp teeth and a long, thin tongue that slowly slithers from its vibrating throat like a snake. With his free arm, Shinji cautiously reaches up to cradle the side of its face, causing it to almost flinch away and bite his arm until he speaks.

“Kaworu… I’m here now, it’s okay. You don’t need to be scared, I’m right here,” Shinji keeps his tone slow and even, trying to hide the fear that was practically pouring off of him. His hand slides lower to the side of its neck, running it softly over the leathery, knotted flesh that was exposed between plates of hard bone-like chiton to listen to the long, sighing purr it makes, the grip of its arms relaxing enough so that his other arm can slide free, this one aiming for its abdomen. Shinji feels carefully along each undulating plate of its stomach until, finally, he finds what he’s looking for, “Oh, Kaworu…”

Shinji brushes his index finger over a chink in between two of its overlapping pelvic plates, which was slowly growing wider as Kaworu became more aroused. He smiles up at it as he presses two fingers between the plates to stretch it open wider, the first few inches of its ovipositor sliding from underneath with a wet, warm sound that sends shivers across his body. Kaworu stares down at him with rapt intensity as it breathes harder, the spaces between its exoskeleton widening to show the soft, vulnerable tendons that lace them together. A low purr vibrates through its body as the thick quills covering what was once it’s scalp rattle together in interest, it’s lowermost set of arms stretching out to clutch Shinji to its body.

Shinji is brought back to present as his face was now pressed to its rough breast, having been so lost in his ministrations that he had barely noticed any of its movements. All at once, he feels himself tipping backwards as Kaworu dismounts from the wall, his arms shooting out to clutch it around the middle as it stands on both its dominant arms and legs, while its two other sets of arms clutch him carefully as it carries him back to its den.

Of course, Shinji already knew about the nest that he and Kaworu had made, consisting mostly of dirty clothes and a few towels as some foresight, as things sometimes got a little messy. Smartly enough, Shinji had also stowed away plenty of rations and extra towels just in case it wouldn’t let him leave, though he rarely needed to rely on them for too long, as it would typically leave the room to raid the kitchen for any food or drink he would need. With a small _oof_ , it drops him into the semi-circle shaped den before easily reaching back with one of its massive arms to shut the door behind them, instantly focusing back on him.  

“Mmm, wait a second…” Shinji sighs as he kicks his legs up around its center, crossing his ankles together to adequately hold on as he reaches down to grab its ovipositor with a shaky, sweating hand, his body burning with a bizarre eagerness that only happened during these heat periods. Kaworu, however, decides otherwise as it growls and jerks itself back, much to his confusion. It becomes clear a moment later as it trails down his shivering body, it’s mouth opening and facial plate lifting to show the veiny sinews of its face, exposing bulbous, pulsing eyes that gaze up at him with unknowable hunger. With a slow nod, Shinji instead reaches down and pulls up his shirt to expose the rest of his body to the waiting maw in front of him, watching the thin, slick tongue slither from the depths of its throat to coil around his penis with a precision that only comes from hours of practice. A moan echoes from his chest to go along with the possessive growl it levels back at him, his hips jumping up to get more of the soft, undulating throat now wrapped so delicately around him.

With the sweet slide of its tongue, coupled with the calculated movements of its internal mouth parts, it only takes him a minute to come, reaching out to grip at its facial plate as he tosses his head back and groans, filling up its throat with his cum. It continues to suckle on Shinji for a bit longer before pulling back, leaning back up to fully stretch out its mandibles and open its inner jaw to show him it’s cum slathered throat. Shinji chuckles as he reaches up to hook his fingers under its labium, pulling it forwards so that he could kiss it on the soft membrane above its top row of teeth. He falls back into the nest when Kaworu moves forwards, deepening the kiss by sliding its tongue into his waiting mouth. 

Despite its lack of lips, Shinji really did find it a good kisser… he wraps his arms snuggly around its neck as he sucks down the length of its tongue, his face now precariously within reach of its fanged mandibles. At this range, he could hear the gentle, chittering coos it was making, opening his eyes to see that it had narrowed its own into a pleased squint. Shinji opens his mouth to let its tongue retract, carefully petting the rough bristles along its spine as he continues to pepper small kisses over the now drooling interior of its mouth, using his other hand to snake down its body to reach for its ovipositor, which had emerged to its full, eighteen-inch length. Initially it growls when he touches it, but stops a second later as he begins to stroke his hand up and down, playing with the ridges and folds he knew it liked. Kaworu slowly retracts its face plate so that it could nuzzle firmly at his chest, it’s lowermost arms reaching up to stroke along the sides of his body before reaching his nipples.

“Ah, yeah- there,” Shinji moans as he tightens his hand around its dick, tossing his head back when it’s tongue curls around one of his nipples while its claws tickle over his stomach. He was already starting to get hard again from the heavy petting he was receiving, but this time he didn’t want the focus to be on him. With caution, he pulls his hand away from its length to press it firmly against its chest, pushing slightly, “Kaworu… you now. It’s your turn…” 

As soon as he says that, it pulls its hands and face away from his body, glaring down at him with something that seemed like a mix of confusion and malice. Shinji manages to sit up, running his hand up and down its side as his other strokes its forehead, noting with a smile that it was beginning to purr louder than before. He gently pushes it sideways, keeping it focused on the other touches until, finally, it was rolled onto its back. He straddles its hips so that his cock was settled against the base of its ovipositor, rocking his hips slightly just to feel the viscous slurry of natural lubricant it was producing against his skin, wrapping one hand around the base of its length while his other plays with the quickly softening tip. 

“Kaworu… so naughty, getting loose for me,” Shinji croons, pressing his index finger against the blunt, angled tip of its cock, feeling it unfold under his touch. The warm petals of flesh split open like a blooming flower, revealing the wet interior of its ovipositor which he quickly dips his finger into, relishing in its whimpering chitter, “Like that? Oh, you really feel that, don’t you… I’m sure you’re going to like this better.” 

Raising onto his knees, Shinji reaches back to press two fingers into himself, keening at the sudden stretch. Thankfully, he was still loose from the night before, moving his fingers in and out a few times before finally pulling them out. He looks back at Kaworu, seeing how focused it was on his movements and how hard it was breathing, nodding slowly as he reaches out to grab the hands of its middlemost arms, bringing them up to his waist. Letting its instinct take over, Shinji relaxes himself and lets it lift him upright, placing him over its ovipositor and lowering him onto it. He winces at first, spreading his legs to allow it easier entrance, but gasps in relief as it presses inside. Thighs shaking, he lets himself be manipulated by Kaworu’s hands so that his spine was arched back and his hands were pressed to its thighs, his knees slowly pressing down against the mattress.

Finally, after what feels like a small eternity for Shinji, he was sitting on its hips with its length completely inside of him. He looks down to see a small bulge at the base of his stomach, running a hand over it to feel the soft pulsations of its ovipositor pierced deep within his body, acclimating to the tight heat of the hole it was in while Kaworu stares quietly up at him. It had been uncharacteristically silent ever since he had begun to take it inside him, its eyes locked on him and a low buzz permeating the air around them. Its hands were gentle despite the situation, simply resting around his waist until needed, though its other arms were now moving to touch him, with the larger upper set resting on his calves while the lower ones reach up to hold his shoulders.

“Mm… Kaworu… you can…” Shinji sighs loudly, his heart thudding louder as it starts to shift below him. At his words, it immediately begins to lift him up, pulling him back down just as quickly. Even though he was extremely experienced at this, he still feels the same vibrating warmth from his first time wash over the back of his head, allowing his body to ragdoll in its arms as he focuses on the familiar tingle spreading down his back. It felt as though his body was unspooling around him, falling away to leave him weightless and lost in the movements of the other. Kaworu croaks quietly below him, the spaces between its scales widening once again to expose the thin tendrils between them, each reaching up in an attempt to touch and taste him, to sense its lover as he rocks lovingly against its body, arms tensing to bring him closer. With his body as relaxed as it was, Shinji faceplants against its chest with a quiet groan from the impact, his voice swallowed up as thousands of sensory organs brush over his skin, pushing against it to dig into follicles and pores. The margins of his being suddenly feel so much wider as Kaworu connects to him, their AT Fields lowering in sync.

**_SHINJI_ ** _,_ the voice makes him jump a little, looking around with just his eyes for the source when a second word comes through, **_US_ ** _._ Shinji hums softly in response to the clarification, turning his head just enough to look up at its face.

_Yes, us. I know, Kaworu,_ Shinji thinks purposefully, seeing the flutter of movement behind its mask of bone. It pulls back a second later to show its slitted eyes and exposed set of internal secondary teeth, a loving purr replacing the droning hum, and it takes a sizable amount of his willpower to not wriggle free and slide his tongue over those long, grey incisors. His mind is taken elsewhere when it starts to move again, its hips bucking up from underneath him and its hands holding him in place.

**_MINE_ ** , Kaworu sighs in thousands of inhuman voices and languages, it’s lower hands digging their claws against his back as its movements increase in speed and voracity. Gritting his teeth together to bear with the pain, Shinji groans loudly as he moves his hips in time with each shallow thrust it gives, still keeping close while the gossamer burrows deeper. A second word echoes into him between gasps, forcing him to give in and let the tears flow down his face from the sheer magnitude of the emotions being conveyed by the connection. **_LOVE_ ** _,_ it sings in tongues beyond comprehension, overwhelming him with a single word. 

Shinji cries out as he finally comes, gripping its chest plate tightly and grinding his hips down hard. Between gasps for air, he hears the word echoed over and over again all around him until the voice is broken by a deep, howling roar that reverberates through the room and rattles the windows. It’s hands tighten around his back and legs, holding him in place as it orgasms just when he hits his peak. The first gush of lubricating fluid pours into him followed by a small clutch of tiny, marble-sized eggs, his body easily relaxing to accept the brood as well as each successive one. Kaworu finally relents after six more were put into place, it’s hands softly caressing his body while he comes down from the emotional overload.

“Oohhh… that f-feels…” Shinji murmurs slowly, giving up on speaking to instead focus on learning how to breathe again, _I really needed that, Kaworu. I feel so full now. Let me rest with you for a while, I need you here,_ he turns to gaze up at its face to give it a knowing look, nuzzling it’s chest.

**_STAY_ ** _,_ Kaworu confirms, pulling him up and bringing its head forward just enough so that it would be within kissing distance without severing the connection or pulling out. Shinji smiles at the sentiment, leaning forwards to peck over its large set of chisel-shaped inner teeth before actually starting to kiss it, focusing on the tender membranes between its two jaws. It chitters in delight at the open display of affection, wrapping its arms around him with its left upper hand cupping the back of his head, keeping him warm and safe. **_LOVE_ ** _,_ the word comes through quieter this time, like a whisper against the back of his neck, and he drinks it in like it's the last thing he’ll ever hear.

_I love you too, Kaworu. More than anything,_ Shinji gives it a few more kisses before relaxing back against its chest, tucking his head against the striated, leathery skin of its neck. Somewhere deep inside of him, he feels Kaworu smile as he drifts off into a long, quiet nap, listening to it murmur words of intimacy that don’t exist but make sense all the same.

 


End file.
